An elevator hall in a building is provided with a hall door serving as a gate to an elevator car. The hall door is usually shut securely to block the communication between the elevator hall and the side of a hoistway in which the elevator car travels upwardly and downwardly, and is open and closed synchronously with the opening and closing of the elevator car when the elevator car reaches the elevator hall.
The hoistway in which the elevator car is vertically movable is provided so as to vertically extend from the lowest floor to the highest floor of the building. In the hoistway, there is a governor rope hanging from a sheave, and a counterweight vertically movable in the opposite direction to the moving direction of the elevator. The wall of the hoistway and the elevator car allow a rather large space.
Therefore, since it is not completely possible to deny the possibility that the hoistway serves as a chimney extending in vertical directions when a fire occurs in the building, the elevator hall door is formed of a refractory material, such as a metal, so that the fire and smoke can hardly enter into the hoistway.
If a building fire occurs, there are some cases where the elevator hoistway serves as a passage for smoke and fire to sequentially introduce to the upper floor, causing further increased damage by the spread of the fire. The reason why smoke and fire enter into the hoistway is that the elevator hall door arranged on the elevator hall falls off due to the damaged deformation caused by heat so that the elevator hall gate serves as a smoke inlet.
FIG. 11 shows an elevator hall door which is utterly deformed by being exposed to heat caused by a fire on an elevator hall. In FIG. 11, reference number 1 denotes a door frame 1 which is fixed to a wall 2, and reference number 3 denotes an elevator hall door. In FIG. 11, the left side is a hoistway, and the right side is an elevator hall. Reference number 4 denotes a header case which is fixed to the top side portion of the entrance of the wall 2, and reference number 5 denotes a sill which is fixed to a gate floor 6. A hanger roller 7 is supported on a hanger 8 which is mounted on the top end portion of the elevator hall door 3. On the other hand, a hanger rail 9 with which the hanger roller 7 engages so as to be capable of rolling thereon is mounted on the header case 4, and the elevator hall door 3 is open and closed while the hanger roller 7 rolls on the hanger rail 9. On the bottom end portion of the elevator hall door 3, a guide shoe 10 sliding in a guide groove of the sill 5 is mounted.
As shown in FIG. 12, the door panel of the hoistway door 3 comprises a surface board 11 constituting a design surface, a back board 12, and a reinforcing member 13 for reinforcing them.
If the elevator hall door 3 is exposed to heat when a fire occurs in the building, the door panel of the elevator hall door 3 starts to be gradually deformed so as to be warped as shown in FIGS. 11 and 12. If the elevator hall door 3 is further exposed to heat, the elevator hall door 3 falls away from the hanger rail 9 and the sill 5, allowing fire and smoke to enter into the hoistway from opening space of the elevator hall, so that there is the possibility of spreading the fire to upper floors.
To taking countermeasures for preventing such a hazardous situation, there are know measures to utilize elongated holes, which are provided in connecting portions of the back board 12 to the surface board 11 and the reinforcing member 13 for allowing them to slide in vertical directions, to absorb the difference in heat expansion between the back board 12 and the surface board 11 and reinforcing member 13. These elongated holes enable the door panel to suppress the deformation to prevent from falling off.
However, although the above described conventional elevator hall door can absorb the difference in elongation in vertical directions between the back board 12 and the surface board 11 and reinforcing member, the door panel of the elevator hall door is restricted in depth and lateral directions, so that it is insufficient to suppress the deformation of the door panel even if the deformation is suppressed to some extent.
In addition, all of component parts of the door hanger apparatus of the elevator hall door 3 are difficult to be formed of fire resistant materials for structural reasons. For example, the hanger roller on the reverse side of the header case 1 on the elevator platform is provided with a cushioning material, such as a plastic, at least on the outer peripheral surface thereof in order to ensure the quietness of operation of the elevator hall door.
Although the cushioning material itself does not easily melt by using a fire-resistant plastic material or the like, it is considered that the cushioning material melts due to heat of a high temperature during a fire in a special case beyond expectations.
If the melted cushioning material falls while it has heat of a high temperature, if a part thereof enters the hoistway from the elevator hall door 3, and if a lubricating oil or the like exists in the hoistway in the vicinity thereof, it is considered that the melted cushioning material takes fire to cause a secondary fire.